/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.solr.util;

/**
 * @version $Id: NumberUtils.java 555343 2007-07-11 17:46:25Z hossman $
 */
public class NumberUtils {





  public static String int2sortableStr(int val) {
    char[] arr = new char[3];
    int2sortableStr(val,arr,0);
    return new String(arr,0,3);
  }

  public static String int2sortableStr(String val) {
    return int2sortableStr(Integer.parseInt(val));
  }

  public static String SortableStr2int(String val) {
    int ival = SortableStr2int(val,0,3);
    return Integer.toString(ival);
  }


  public static String long2sortableStr(long val) {
    char[] arr = new char[5];
    long2sortableStr(val,arr,0);
    return new String(arr,0,5);
  }

  public static String long2sortableStr(String val) {
    return long2sortableStr(Long.parseLong(val));
  }

  public static String SortableStr2long(String val) {
    long ival = SortableStr2long(val,0,5);
    return Long.toString(ival);
  }

  //
  // IEEE floating point format is defined so that it sorts correctly
  // when interpreted as a signed integer (or signed long in the case
  // of a double) for positive values.  For negative values, all the bits except
  // the sign bit must be inverted.
  // This correctly handles all possible float values including -Infinity and +Infinity.
  // Note that in float-space, NaN<x is false, NaN>x is false, NaN==x is false, NaN!=x is true
  // for all x (including NaN itself).  Internal to Solr, NaN==NaN is true and NaN
  // sorts higher than Infinity, so a range query of [-Infinity TO +Infinity] will
  // exclude NaN values, but a query of "NaN" will find all NaN values.
  // Also, -0==0 in float-space but -0<0 after this transformation.
  //
  public static String float2sortableStr(float val) {
    int f = Float.floatToRawIntBits(val);
    if (f<0) f ^= 0x7fffffff;
    return int2sortableStr(f);
  }

  public static String float2sortableStr(String val) {
    return float2sortableStr(Float.parseFloat(val));
  }

  public static float SortableStr2float(String val) {
    int f = SortableStr2int(val,0,3);
    if (f<0) f ^= 0x7fffffff;
    return Float.intBitsToFloat(f);
  }

  public static String SortableStr2floatStr(String val) {
    return Float.toString(SortableStr2float(val));
  }


  public static String double2sortableStr(double val) {
    long f = Double.doubleToRawLongBits(val);
    if (f<0) f ^= 0x7fffffffffffffffL;
    return long2sortableStr(f);
  }

  public static String double2sortableStr(String val) {
    return double2sortableStr(Double.parseDouble(val));
  }

  public static double SortableStr2double(String val) {
    long f = SortableStr2long(val,0,6);
    if (f<0) f ^= 0x7fffffffffffffffL;
    return Double.longBitsToDouble(f);
  }

  public static String SortableStr2doubleStr(String val) {
    return Double.toString(SortableStr2double(val));
  }



  // uses binary representation of an int to build a string of
  // chars that will sort correctly.  Only char ranges
  // less than 0xd800 will be used to avoid UCS-16 surrogates.
  public static int int2sortableStr(int val, char[] out, int offset) {
    val += Integer.MIN_VALUE;
    out[offset++] = (char)(val >>> 24);
    out[offset++] = (char)((val >>> 12) & 0x0fff);
    out[offset++] = (char)(val & 0x0fff);
    return 3;
  }

  public static int SortableStr2int(String sval, int offset, int len) {
    int val = sval.charAt(offset++) << 24;
    val |= sval.charAt(offset++) << 12;
    val |= sval.charAt(offset++);
    val -= Integer.MIN_VALUE;
    return val;
  }

  // uses binary representation of an int to build a string of
  // chars that will sort correctly.  Only char ranges
  // less than 0xd800 will be used to avoid UCS-16 surrogates.
  // we can use the lowest 15 bits of a char, (or a mask of 0x7fff)
  public static int long2sortableStr(long val, char[] out, int offset) {
    val += Long.MIN_VALUE;
    out[offset++] = (char)(val >>>60);
    out[offset++] = (char)(val >>>45 & 0x7fff);
    out[offset++] = (char)(val >>>30 & 0x7fff);
    out[offset++] = (char)(val >>>15 & 0x7fff);
    out[offset] = (char)(val & 0x7fff);
    return 5;
  }

  public static long SortableStr2long(String sval, int offset, int len) {
    long val = (long)(sval.charAt(offset++)) << 60;
    val |= ((long)sval.charAt(offset++)) << 45;
    val |= ((long)sval.charAt(offset++)) << 30;
    val |= sval.charAt(offset++) << 15;
    val |= sval.charAt(offset);
    val -= Long.MIN_VALUE;
    return val;
  }


}
